peter,
i believe fran is talking about more than one sound per track, in different variations. the same track, ex. bass, can contain fretless on intro1, wet on intro2, pick on intro3, etc. but also synth on var1, acoustic on var2, and so on.
that indeed might be 18 sounds to start with, but it could go up to 3x18 as you described, still, i am not so sure. i never tried.
that is more than enough anyway.

too bad roland does not allaw two drum tracks... ;(